Governing device for compound engines



(N0 Model.) 4 Sheets-Sheet 1.

M. c. BULLOCK. GOVERNING DEVIGE FOR COMPOUND ENGINES.

v Patented Oct. 1, 1895.

ANDREW EERMIAM. PHOYOUTMQWASRINGTDNJZC.

(No' Model.) 4 Sheets-Sheet 2.

M. 0. BULLOCK. GOVERNING DEVICE FOR COMPOUND ENGINES.

No; 547,242. Patented Oct. 1, 1895.

I jE- M. 0. BULLOCK. GOVERNING DEVIGE FOR COMPOUND ENGINES.

4 SheetsSheet 3;

(No Model.)

No. 547,242, Pmnted 0 11.1, 1895.

- ANDREW EGRAHANLPHOTO UTKQWASMING'TOMIIC (No Model.) 4 sheets -sheet 4.

M. O. BULLOCK.

' GOVERNING DEVICE FOR COMPOUND ENGINES. No; 547,242; Patented 001;.1,1895.

ANDREW KERMMM. PHU'lO-LITHQWASIIINGTONJL.

warns MILAN C. BULLOCK, OF CHICAGO, ILLINOIS.

GOVERNING DEVICE FOR COMPOUND ENGINES.

SPECIFICATION forming part of Letters Patent No. 547,242, dated October1, 1895. Application filed September 6, 1893- Serial No. 184,88L (N0model.)

To all whom it may concern:

Be it known that I, MILAN O. BULLooK, of Chicago, in the county of Cookand State of Illinois, have invented certain new and useful Improvementsin Governing Devices for Gompound Engines; and I do hereby declare thatthe following is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, which form a part of this specification.

This invention relates to improvements in governing devices for compoundsteam-engines, and it embraces, among other features, improvements ingoverning devices of that class shown and described in a prior patentgranted to me September 5, 1893, No. 504,691, wherein the steam-passageleading from a high to a low pressure cylinder is provided with anexhaust-steam outlet provided with a valve, which acts to maintain saidoutlet normally closed, but which is open to permit the escape ofexhaust-steam from the highpressure cylinder whenever the speed of theengine reaches a predetermined limit, and to thereby prevent suchexhaust-steam from acting on the piston of the low-pressure cylinderuntil the engine again resumes its normal speed.

The invention consists in the matters hereinafter described, and pointedout in the appended claims.

While my invention is herein shown as ap plied to a two-cylindercross-compound engine, yet the principles of the invention may beapplied to triple or quadruple and to other forms or types ofmnltiplecylinder expansion engines.

In the accompanying drawings, Figure 1 is an end elevation of across-compound engine provided with my improvements. Fig. 2 is anelevation of the low-pressure-cylinder side of the engine. Fig. 3 is ageneral plan view of the engine. Fig. 4 is a detail horizontal sectionshowing the valve at the outlet of the receiver and its immediateoperating mechanism, said section being taken on line 4 4 of Fig. 5.Fig. 5 is a vertical section through the same valve, taken on line 5 5of Fig. 4. Fig. 6 is a bot-tom plan view of the valve-disk. Fig. 7 is adetail view of a cam mechanism through the medium of which the movementof the valves is controlled. 8 is a detail section on line 8 8 of Fig.1.

My improvements are shown in this instance as applied to that type ofengine commonly known as the cross-compound, or that in which-the highand low pressure cylinders are placed side by side or parallel with eachother. Said engine may be provided with any preferred form ofvalve-gear, that shown in the drawings being of the well-known Oorlisstype. The engine, furthermore, may be controlled by any preferred formof governor, the one herein shown being the common ballgovernor usuallyused in connection with a Corliss valve-gear.

A is the high-pressure cylinder of the engine and B thelow-prcssurecylinder thereof, exhaust-steam being conducted from the high to the lowpressure cylinder bya pipe or passage O, which will usually be made ofo0nsiderable capacity and which constitutes what is known as thereceiver. The form of the receiver in thisinstance is that usuallyemployed in this type of engine, consisting ofa large pipe or chamberplaced transversely between and at a lower level than the cylinders, andconnected at one end with the lower end of the high-pressureexhaust-pipe O, and at the other end with the lower end of thelow-pressure steam-supply pipe 0 The upper ends of said pipes C and Care connected with the cylinders A and B in any preferred manner; saidpipes being shownin this instance as attached to the under sides of thesaid cylinders. At the exit end of the receiver (J, in the instanceshown in the pipe 0 I provide avalve D for closing said pipe, and inconnection with said valve operative connections by which the valve maybe operated by the engine-governor. In the passage leading from thehigh-pressure cylinder to the receiver, in this instance in pipe 0, Iprovide an exitpassage C communicating with the open air or with acondenser, and in said exit-passage is placed an outwardly-openingrelief-valve E, adapted to open automatically when a predeterminedpressure is reached. This con- Fig.

struction enables the exhanst-steam from the high-pressure cylinder tobe discharged into the open air or into the condenser when the desiredlimit of speed is reached, and the closing of the valve D at the exitend of the receiver acts to cut off steam-supply from the low-pressurecylinder and at the same time to confine the steam in the receiver untilthe pressure therein becomes so great as to overcome the resistance ofthe relief-valve E, when the latter opens and allows escape of steamfrom the receiver in quantity sufficient to prevent the pressure thereinbeing in excess of that at which the relief-valve is set to open, steamheld in the receiver under such' pressure being retained therein untilthe engine resumes its normal speed, when it passes to the low-pressurecylinder. In this instance the exhaust-passage C is in the form of abranch pipe forming part of a removable section 0 of the high-pressuresteam-exhaust pipe 0, and the relief-valve E has the form of an ordinaryweighted pop safety-valve, the weight of which may be adjusted to allowthe escape of steam at any desired pressure. The said relief-valve-willpreferably be set to open at such pressure as to maintain in thereceiver approximately the same pressure that exists therein during theusual or normal action of the engine, the object being to maintain suchsteam-pressure in the receiver during the time that the valve D isclosed, so that when it is opened and the low-pressure cylinder resumesits work steam will be admitted to said low-pressure cylinder at normalworking pressure only, and great or dangerous strains on the engine atsuch times will thereby be prevented.

The valve D at the exit end of the receiver is shown in detail in Figs.4, 5, and 6, and is constructed as follows: In the pipe G which leadsfrom the receiver to the low-pressure cylinder, is located a diaphragm Cprovided with segmental ports 0' c. The diaphragm is shown as madeintegral with a section 0 of the pipe 0 which is directly secured to thelow-pressure cylinder. Beneath and in contact with the said diaphragm isan oscillatory valve-disk F, having ports ff of segmental form whichoperate in connection with the correspondiugly-shaped ports 0 c topermit the passage of steam from the receiver to the low-pressurecylinder. Said valvedisk is supported in contact with the said diaphragmby a pin f, which is secured to the disk and passes through thediaphragm and is provided with a head or nut at its upper end and actingto hold the disk in contact with the diaphragm. Said valve-disk beingbelow the diaphragm, it is pressed against the same by the steam-pressure within the receiver, so that leakage of steam is prevented at thetimethe valve is closed. The oscillating Valve described may be operatedin any suitable manner, but as herein shown itis actuated through themedium of a horizontally-movable rod G,

which passes through the walls of the pipe 0 and is connected with thevalve-disk by means of two flexible strips or strands g g, each of whichis attached at one end to the disk and at its opposite end to the rod,and which rest for part of their length uponthe outer cylindric surfaceof the disk in the manner illus-' trated. Said rod Gr is shown asextending through a horizontal slot 0 formed in the casing C of thevalve, within which slot the strands g g are located. Said strands areshown as connected with the valve-plug by means of lugs g through whichpass bolts g, engaged with loops on the ends of the strands, and asconnected with the red by means of sliding-sleeves 9 to which thestrands are directly attached and which are connected withadjusting-nuts g on the rod by means of collars 9 havinginwardly-extending flanges which engage grooves on both of the sleeves gand nuts g so as to permit the nuts to be turned for tightening thestrands without turning the sleeves to which the strands are attached.

In the particular construction illustrated the valve-disk F is providedat its margin with a cylindric fiangef which fits within thevalve-casing, the purpose of said flange f being to afford a cylindricbearing-surface of suitable width for the strips 9 g, which connect thevalve-disk with the rod. In this instance the rod is shown as passingthrough a stuflingloox 0 secured upon the outer end of the tubularextension 0 which is formed on the valve-casing O for the purpose ofreceiving the end of the strand 9 and the attaching devices by which thestrand is secured to the rod. A similar tubular extension 0 of thevalve-casing receives the end of the rod G at the opposite side of thevalve and is provided with a closing plug 0 having a centralguide-aperture within which the rod slides.

It is obvious that when the valves E and D are both closed the steamwithin the receiver will be bottled up or imprisoned therein, so thatnot only may any excess of exhauststeam from the high-pressure cylinderescape into the open air through the relief-valve and thus be preventedfrom reaching the lowpressure cylinder, but steam already within thereceiver is restrained from acting on the low-pressure cylinder and isconfined Within the receiver for subsequent use as soon as thel0w-pressure cylinder shall again come into action.

Il'O

For the general purposes of the invention the rod G may be moved foractuating the valve D by any suitable connection with the governingdevice of the engine. I have, however, herewith shown a steam-actuatedoperating mechanism in the form of an auxiliary motor for the valve-rod,which is constructed as follows: Said motor in the form shown comprisesan auxiliary steam-cylinder having a steam-valve connectedwith thegovernor and serving to admit steam to one side or the other of thepiston within the cylinder, according to the position of the governor,said piston being suitably connected with the rod G to givereciprocatory motion to the same and to thereby open and close thereceiver= valve. In the form shown His the auxiliary cylinderand II thepiston therein, said piston being attached directly to the end of therod G, which enters the cylinder through the stuffing-box h in the usualmanner. Steam is admitted to the opposite sides of the piston 11 throughsuitable ports h h and is in this instance exhausted through the sameports, the steam supply and (xhaust being controlled by a suitable valveI. The valve shown in this instance is of the well-known hollow pistonform, embracing two short pistons t t at the end of the tubular bodyportion i of smaller diameter. A steam-supply pipe h admits steam to theannular space surrounding the body portion of the valvepiston, thespaces at the ends of the piston are connected by a central passage inthe valve, and an exhaust-pipe 72 communicates with one of said spaces.Attached to the valve I is the usual valve-rod I, which passes through asuitable stuffing-box h and is supported near its outer end by asuitable bracket-bearing J, Fig. 3. Suitable connections are providedbetween the valve-rod and the governor, by which the latter operates thesaid valve, and thereby, through the operation of the auxiliary motordescribed, serves to open and close the receiver-valve.

In the present form of my invention I provide connections between thegovernor and the valve of such nature that the ordinary fluctuations ofthe governor do not affect the position of said valve, and no movementof the latter takes place until the governor has exceeded in itsmovement a predetermined limit. The full freedom and delicacy of actionof the governor is thus preserved during the continuance of its normalconditions. Said connections are, however, so constructed as to quicklymove the valve-rod and valve in one direction whenever the governorexceeds such predetermined limit of movement and in the other oropposite direction when the said governor returns or repasses such limitof movement.

Various connections capable of producing the above-described action maybe devised; but in this instance I have shown for actuating the valve acam mechanism comprisinga pivoted cam K, Figs. 2 and 7, which isprovided with a cam-slot is, engaging a pin Z in one end of the slidingrod L, the opposite end of which is connected with the valve-stem I bymeans of a bell-crank lever M and two connecting-links m. m, Fig. 3. Thecam-slot 7c of said cam is provided with a concentric part 7t, withwhich the pin Z is normally engaged, at the end of which concentric partis a relatively-short eccentric portion 10 beyond which, in the instanceshown, is formed a second concentric portion 10 the radial distancesbetween the two eccentric portions being sufficient to give a desiredtravel to the valve. The cam K is connected with i the governor so as tooscillate with the fluctuations of the same, such connections being inthe present instance shown as provided by means of a connecting-rod N,pivoted at its upper end to a lever N, which is fitted to anyoscillating part of the governor. Said rod N is connected at its lowerend with the cam K or some part rigidly connected to oscillatetherewith, in this instance to an arm 0', which is affixed to one end ofthe shaft 0, to which the cam is rigidly secured and which serves asapivotal support for the said cam. In the form shown the lever N is madeof considerably greater length than the arm O', in order that arelatively-slight fluctuation of the governor may produce a considerableoscillation of the cam. The concentric. portion of the cam-slot is ofsuch length that the ordinary movements of the governor will not swingthe cam far enough to engage the pin I with the eccentric portion W, andit is obvious that unless this is done the valve-rod will remainstationary. Thus, under ordinary circumstances no extra work is done bythe governor beyond the slight force required to oscillate the cam, andconsequently its freedom and delicacy of action are not interfered with.When, however, under an unusual decrease of load or increase ofsteam-pressure, the movement of the governor exceeds the predeterminedlimit, the cam K will be swung so far as to cause the pin 1 to pass theeccentric portion 70 of the slot and thereby shift the valve I. Furthermovement of the governor and cam in the same direction will merely causethe pin to enter farther in the eccentric continuation of the slotwithout affecting the position of the valve, but a re verse movement ofthe cam will return the pin through the eccentric portion of the slotand thus carry the valve back to its first position.

By so constructing the parts that a slight movement of the governor willcause a com siderable oscillation of the cam, as hereinbe fore stated,and by making the eccentric portion of the cam-slot relatively short, aslight movement only of the governor will be required after the properpoint has been reached to move the valve I the full length of itsstroke. In the normal position of the valve the latter is in position toadmit steam to that side of the piston H by which the main valve-portsleading from the receiver are held open. When the valve is moved to theother end of its stroke by an excessive movement of the governor in themanner hereinbetore explained, live steam will be admitted to theopposite end of the cylinder, while at the same time exhaust-steamescapes from that end of the cylinder filled with the same, so that thepiston will be carried in a direction to move the receiver-valve,thereby closing the exit of the receiver, the surplus exhaust-steam fromthe high-pressure cylinder escaping through the exit-passage C The valveI will be held in this position until, as the engine resumes its normalspeed said valve will return to its first position, when steam will beadmitted to force back the piston and again actuate the receiver-valveto bring it to its normal or working position. It'will be obvious thatthe shifting of the piston of the auxiliary motor under the pressure ofsteam will be practically instantaneous and coincident with the movementof the valve I by the governor, and the latter action being quicklyaccomplished at a predetermined point in the movement of said governor,it follows that as the governor passes such predetermined point in itsmovement the receiver-valve D will be instantly opened or closed, as thecase may be. Normally the valves D will be held open in the mannerhereinbefore described, the exhaust-steam from the high-pressurecylinder passing through the exhaust-passage thereof and the receiver tothe low-pressure cylinder in the usual manner, while the governorfluctuates as usual under slight variations of load or steam-pressure.In case, however, the movement of the governor is so great as to exceedthe desired limit of speed, the governor operates in the mannerpreviously described to instantly move said valves, thereby cutting offthe passage of steam already in the receiver to the low-pressurecylinder, so as to relieve the same of further actuatingpressure, andconfining the steam within the receiver for subsequent use when theengine returns to its normal speed. In cases where provision is made forheating the receiver, as by a steam-jacket, as is the case in the engineherein illustrated, the steam thus imprisoned within the receiver willbe maintained at a sufficiently-high temperature and pressure to doeffective work as soon as admitted to the low-pressure cylinder.

The limit of movement of the governor at which the same will operate toactuate the receiver-valve D will usually be at the point at which thesaid governor operates to completely out olf the steam-supply from thehigh-press ure cylinder, so that the engine will be permitted to operatein the ordinary manner and will be controlled by the usual governingdevices until such time as such governing devices shall have reached thelimit of their effectiveness, whereupon the additional governing.

devices, herewith described, will come into play to further and moreeffectively control the engine. The low-pressure cylinder willobviously, after the cutting off of its steamsupply in the mannerdescribed, practically remain inoperative until the governor repassesthe point at which the receiver-valves were closed, but owing to thefact that the steam-supply passage of said low-pressure cylinder willthen be entirely closed, the piston of said low-pressure cylinder willat such time act against a vacuum, which will tend to lessen the speedof the engine and thus aid in quickly bringing the engine to the desiredlimit of speed.

The relief-valve E being set to open at a pressure approximately equalto or not greatly in excess of the normal pressure within the receiver,it follows that when the valve D is again opened, after having beenclosed, steam will be admitted at normal pressure to the lowpressurecylinder at such time. In the absence of said relief-valve, it isobvious that under some circumstances the steam-pressure in the receivermight become very great, the inertia of the fly-wheel and otherrapidlymoving parts of the engine being commonly sufficient to force somuch steam into the receiver as to establish a high pressure therein;but in the construction proposed any excess of the exhaust-steam willescape through the relief-valve and the receiver will remain filled withsteam at a normal or moderate pressure only. It will be noted,furthermore, that inasmuch as the exhaust-valves of the highpressurecylinder are open at the time the piston reaches the end of its strokein each direction, steam thus confined in the receiver will rush intothe cylinder as soon as said exhaust-valves are open, so as to give abackpressure on the piston, and that the piston in its backward movementwill force such steam back again into the receiver, and in doing so willcompress the steam and restore it to its original pressure, or nearlyso. Steam thus entering the cylinder through the exhaustvalves will actby its backward pressure on the piston to retard the engine, and willthus tend to quickly lessen its speed-in other words, the work done bythe piston during its back stroke, in forcing the steam back into thereceiver and compressing it to its original bulk, will tend to quicklyretard the speed of the parts and to thus more promptly bring the engineto its normal speed. It is to be further noted that this action willcontinue ICO during every stroke of the piston until the speed of theengine is properly reduced and steam is again admitted to thelow-pressure cylinder, it being obvious that steam from the receiverwill enter each end of the cylinder and will be forced from the sameback into the receiver at every stroke, so that the same receiver fullof steam is compressed again and again until, by the reduced speed ofthe engine, normal working conditions are restored.

Inasmuch as the steam-pressure in the receiver when made of sizesordinarily employed will be considerably reduced when the steam thereinexpands into the high-pressure cylinder, it will usually be preferable,in order that the back-pressure of steam in the piston may act moreefficiently in retarding the engine, to set the relief-valve to open ata pressure somewhat above the normal pressure invthe receiver. This willnot, under usual conditions, produce objectionable pressure on thelowpressure cylinder at the time of opening the valve D, owing to thelarge size of said lowpressure cylinder as compared with the receiver.The relief-valve will, however, be so set that the effective pressure inthe lowspressure cylinder at the time referred to will not be materiallygreater than that which obtains when the governing devices are not inoperation.

IIO

a rman As a further and separate improvement, I propose to apply to theexhaustpassage of the low-pressure cylinder of a compound engine areceiver the exit-opening of which is provided with a valve which isopened and closed by the operation of the engine-governor inthe samemanner as is the valve D, herein shown as applied to the receiver 0, orthat between two cylinders. By the use of such receiver and valve uponthe low-pressurecylinder I am enabled to secure the same retardingeffect on the piston of said low-pressure cylinder by back-pressure onsaid piston and repeated compression of exhaust-steam within thereceiver as is obtained in the construction hereinbefore described bythe use of the receiver O and valve D. In the use of such receiver andvalve applied to the exhaust of the low-pressure cylinder, the valve maybe controlled by the governor of the engine or by a separate governor,and, furthermore, the valve may be operated by the same devices used tooperate the corresponding valve of the receiver between the cylinders orby separate actuating mechanism. Commonly both valves will be actuatedby the same governing devices, because both valves are desirablyactuated at the same time. A construction of this latter kind is shownin the drawings, in which P is the receiver, and which is connected atone end of the exhaust-pipe P of the low-pressure cylinder B, and itsopposite end with an exit-pipe P leading to the open air or to acondenser. Q indicates a valve at the exit end of the receiver, saidvalve being like the valve D and being operated from the rod G by meansof a'valve-rod R and a centrally-pivoted lever B, engaging the rods Gand R, as shown. The receiver P and valve Q act in the same manner as dothe receiver 0 and valve D as far as the retarding of the moving partsis concerned, the closing of said valve Q establishing a back-pressurein the low-pressure cylinder and resulting in the steam confined in thereceiver repeatedly expanding into the cylinder and being compressedagain into the receiver. An important advantage is gained by applyingthe retarding force of the steam from a receiver to both the high andlow pressure cylinders of a compound engine or to all the cylinders of atriple or quadruple expansion engine, for the reason that by thisconstruction are avoided torsional strains on the shaft and otherdangerous strains which must necessarily come on the parts whenretarding pressure is applied to one cylinder only or to less than allof the cylinders.

In connection with the use of a second receiver applied to alow-pressure cylinder, as above described, and as a still furtherimprovement, I propose to provide a valved passage leading directly fromthe first receiver to the second receiver, said passage beingnormallyclosed,but adapted to be thrown open simultaneously with theclosing of the valves at the exits of the two receivers to admit steamdirectly from the first receiver into the second receiver and thusincrease the back pressure on the low-pressure piston and add greatly toits retarding action. Obviously, however, if the pressure in the secondreceiver is suddenly increased to equal that-of the first receiver,

the retarding force resulting on the great area of the low-pressurepiston may, in some instances, produce dangerous strains upon thedriving-shaft and other parts of the engine. I therefore, also,preferably provide the passage connecting the receivers with a suitablereducing-valve by which the pressure in the second receiver may belimited, as desired. Such reducing-valve may, if desired, be combinedwith the valve, by which the passage is opened and closed by thegovernor, a single valve in this case accomplishing both the controllingof the passage and the limiting of the pressure in the second receiver.In this instance, h0wever,I have shown the two valves as independent ofeach other, the construction being as follows: Connecting thelow-pressure steam-pipe C with the low-pressure exhaustpipe P is a shortpassage or pipe P which is provided with a controlling-valve S of anysuitable type adapted to open and close the passage, said valve being,in this instance, shown as an ordinary plug-valve operated by alever sand connecting-rod s from the oscillatory leverR and normally heldclosed thereby. The pipe P is also provided in this instance, at a pointbetween the low-pressure exhaust-pipe P and the valve S, with anysuitable reducingvalve T, preferably of the ordinary type, capable ofbeing adjusted or set at will to maintain any desired pressure in thesecond receiver when the valve S is open. With such construction it isobvious that the action of the engine will nominally remain unchanged,as before. When, however, the variation in speed be comes so great as toclose the valves D and P in the manner hereinbefore described, the valveS will simultaneously open and permit the flow of steam through the pipeP The pressure of steam in the second receiver will obviously thereby beraised to the extent permitted by the reducing-valve, previouslyadjusted as desired, and exert a correspondingly greater back-pressureon the low-pressure piston, tending to restore the engine to its normalspeed. This feature of improvement is of great value for use oncondensing-engines,inasmuch as in such structures the vacuum ordinarilymaintained by the condenser, and necessarilyobviously equally useful inconnection with any type of governor, and may be used either with a ballor shaft load or speed motor or automatic cutoif governor. Theimprovements described, moreover, are not only applicable to all formsof compound engines, but to marine, as well as stationary engines. Theyare, indeed, particularly adapted for marine engines, because of acharacter to act quickly and positivelyin checking the speed of theengine and thereby preventing racing of the propeller when lifted out ofthe water.

I desire not to be limited to the details of construction shown or toany specific details of the devices for carrying out my invention, itbeing obvious that various forms of mechanism may be designed which willembody the general principles of construction and operation embraced inmy invention.

Some of the advantages obtained by the use of the features ofconstruction described in the passage connecting the high and lowpressure cylinders, may be secured by the use of a valved dischargeopening or outlet, permitting the escape of steam from the high-pressure cylinder, in connection with a single valve located at any pointbetween the said outlet and the low-pressure cylinder and operated bythe governor in the same manner as here inbefore described, in caseswhere the exhaustpipe of the high-pressure cylinder leads directly tothe low-pressure cylinder and where there is practically no receiver,or, in other words, where the receiver is so small that the quantity ofsteam contained therein is insignitlcant. In such case steam from thehighpressure cylinder will be allowed to escape therefrom, while at thesame time access of steam to the low-pressure cylinder will beprevented, so that the piston of the latter will work against a vacuumand thus tend to quickly retard or diminish the speed of the engine inthe same manner as hereinbefore stated, although such a structure wouldnot possess the advantage of storing or holding the steam in thereceiver for repeated compression and subsequent use.

I claim as my invention- 1. A governing device for compound enginescomprising a normally closed outlet in the steam passage which leadsfrom the high to the low pressure cylinder, said outlet being providedwith a relief valve and a normally open valve controlled by the enginegovernor, located in said steam passage between said outlet and the lowpressure cylinder, substantially as described.

2. A governing device for compound engines comprising a normally closedoutlet in the steam passage which leads from the high to the lowpressure cylinder, said outlet being provided with a relief valve, anormally open valve in the said steam passage between the outlet passageand the low pressure cylinder, and a governor acting to close said lastmentioned valve when the engine reaches a predetermined limit of speed,substantially as described.

3. The combination with high and low pressure cylinders and anintermediate receiver, of a relief valve applied to the receiver, anormally open valve at the exit of the receiver and a governor acting toclose said valve when the engine reaches a, predetermined limit ofspeed,substantiallyas described.

4. The combination with high and low pressure cylinders of a receiverbetween the cylinders, areceiver connected with the exhaust passage ofthe low pressure cylinder, nor

mally open valves at the exit ends of both receivers, a governor actingto open and close both of said valves when the engine reaches apredetermined limit of speed, and a relief valve applied to the receiverbetween the cylinders, substantially as described.

5. A governing device for compound engines comprising a normally openvalve adapted to close the low pressure exhaust pipe, a normally closedpassage for admitting an auxiliary steam supply between the cylinder andvalve, and means controlled by the governor for simultaneously closingsaid valve and opening said passage, substantially as described.

6. A governing device for compound ongines comprising a normally openvalve in a low pressure exhaust pipe, a passage leading from the lowpressure steam pipe to the low pressure exhaust pipe between thecylinder and valve, a valve normally closing said passage and meanscontrolled by the governor for simultaneously closing the valve in theexhaust pipe and opening the valve in the passage, substantially asdescribed.

7. A governing device for compound ongines comprising a normally openvalve adapted to close the low pressure exhaust pipe, a normally closedpassage leading from the low pressure steam pipe to the low pressureexhaust pipe between the valve and cylinder, a reducing valve in saidpassage and means controlled by the governor for simultaneously closingthe valve in the exhaust pipe and opening the passage, substantially asdescribed.

8. A governing device for compound engines comprising a receiver betweenthehigh and low pressure cylinder, a normally closed valve at the outletof said receiver, a normally open valve in the low pressure exhaustpipe, a normally closed passage leading from a point on the receiverbetween the valve therein and the high pressure cylinder to a point onthe low pressure exhaust pipe between the valve therein and the lowpressure cylinder, and means controlled by the governor forsimultaneously closing said valves and opening said passage when theengine reaches a pre determined limit of speed, substantially asdescribed 9. A governing device for compound engines comprising areceiver between the high ICC and low pressure cylinder, a normallyclosed valve at the outlet of said receiver, a normally open valve inthe low pressure exhaust pipe, a normally closed passage leading from apoint on the receiver between the valve therein and the high pressurecylinder to a point on the low pressure exhaust pipe between the valvetherein and the low pressure cylinder, a reducing valve in said passage,and means controlled by the governor for simultaneously closing saidvalves and opening said passage when the engine reaches a predeterminedlimit of speed, substantially as described.

10. A governing device for compound engines comprising a receiverbetween the high and low pressure cylinder and provided with a reliefvalve, a normally closed valve at the outlet of said receiver, anormally open valve in the low pressure exhaust pipe, a normally closedpassage leading from a point on the receiver between the valve thereinand the high pressure cylinder to a point on the lowpressure exhaustpipe between the valve therein and the low pressure cylinder, a reducingvalve in said passage, and means controlled by the governor forsimultaneously closing said valves and opening said passage when theengine reaches a predetermined limit of speed, substantially asdescribed.

In testimony that I claim the foregoing as my invention I aflix mysignature in presence of two witnesses.

MILAN C. BULLOCK.

Witnesses:

HENRY H. CARTER, TAYLOR E. BROWN.

